Xuan Xaioyan, Li Shanshan, Lou Xi, Zheng Xianzhao, Li Yunyun, Wang Feng, Gao Yuan, Zhang Hongyan, He Hongliu, Zeng Qingru
Department of Pathology, The First Affiliated Hospital and Key Laboratory of Tumor Pathology, Zhengzhou University School of Medicine, Zhengzhou, Henan, China.
Mol Biol Rep. 2015 May;42(5):907-15. doi: 10.1007/s11033-014-3828-8. Epub 2014 Nov 19.
Stat3 alters the expression of its downstream genes and is associated with tumor invasion and metastasis in several human cancers. Its role in esophageal squamous cell carcinoma (ESCC) has not been well characterized. We examined the tumor sections of 100 cases of ESCC by immunohistochemistry and observed significant overexpression of Stat3 in the cytoplasm of 89% of ESCC cells and of phosphorylated Stat3 (p-Stat3) in the nuclei of 71% of ESCC when compare with normal esophageal mucosa (72%, p = 0.02; and 31%, p = 0.001). Overexpression of Stat3 and p-Stat3 positively correlated with that of matrix metalloproteinase-2 (MMP2), a known regulator for cell migration, in 65% of ESCC while only 26% shown in benign esophageal mucosa. To further investigate the association of Stat3 with tumor metastasis in vitro, invasion of EC-1 cells (a human ESCC cell line) were investigated with Boyden chambers. The results showed that transfection of Stat3 not only promoted invasion of EC-1 cells but also significantly induced MMP2 expression in a dose-dependent manner. In contrast, suppressing expression of endogenous Stat3 mRNA and protein by Stat3 siRNA significantly reduced EC-1 cell invasion and MMP2 expression. A high-affinity Stat3-binding element was localized to the positions of 648-641 bp (TTCTCGAA) in the MMP2 promoter with electrophoretic mobility shift assay. Our results suggest that Stat3, p-Stat3, and MMP2 were overexpressed in ESCC and associated with invasion of ESCC; and Stat3 up-regulated expression of MMP2 in ESCC through directly binding to the MMP2 promoter.
信号转导及转录激活因子3（Stat3）可改变其下游基因的表达，并与多种人类癌症的肿瘤侵袭和转移相关。其在食管鳞状细胞癌（ESCC）中的作用尚未得到充分阐明。我们通过免疫组织化学检查了100例ESCC的肿瘤切片，发现与正常食管黏膜相比，89%的ESCC细胞胞质中Stat3显著过表达，71%的ESCC细胞核中磷酸化Stat3（p-Stat3）显著过表达（分别为72%，p = 0.02；和31%，p = 0.001）。在65%的ESCC中，Stat3和p-Stat3的过表达与基质金属蛋白酶-2（MMP2，一种已知的细胞迁移调节因子）的过表达呈正相关，而在良性食管黏膜中仅26%呈正相关。为了进一步研究Stat3与体外肿瘤转移的关系，我们用Boyden小室研究了EC-1细胞（一种人类ESCC细胞系）的侵袭情况。结果表明，转染Stat3不仅促进了EC-1细胞的侵袭，还以剂量依赖的方式显著诱导了MMP2的表达。相反，用Stat3小干扰RNA抑制内源性Stat3 mRNA和蛋白的表达显著降低了EC-1细胞的侵袭和MMP2的表达。通过电泳迁移率变动分析，在MMP2启动子中648 - 641 bp（TTCTCGAA）位置定位到一个高亲和力的Stat3结合元件。我们的结果表明，Stat3、p-Stat3和MMP2在ESCC中过表达，并与ESCC的侵袭相关；Stat3通过直接结合MMP2启动子上调ESCC中MMP2的表达。
